[unreadable] This application is for support of collaborative research conducted by Dr. Timothy Ryan (U.S. Principal Investigator) and Dr. Felipe Barros (Foreign Collaborator; Chile). The U.S. P.I. has a long standing interest on the regulation of vesicle traffic in synaptic terminals, and how this traffic impacts synaptic function. The current proposal extends the breadth of his investigations by considering how synaptic activity is matched by glucose transport and how the metabolic load is shared between neurons and their surrounding astrocytes. The Foreign Collaborator, Dr. Felipe Barros, has experience on the mechanisms of glucose transport activation by metabolic stress and has recently developed methods based on confocal microscopy for realtime measurement of hexose transport in single astrocytes and neurons. The proposal, based on fluorescence imaging, will combine the know how of the US laboratory on synaptic transmission with the expertise of the Chilean laboratory on glucose transport. It is expected that this research will shed new light on the molecular mechanisms that underlie functional imaging of the brain in vivo. [unreadable] [unreadable]